USPTO Patents Application 10687850

(U) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

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(43) International Publication Date (10) International Publication Number

16 January 2003 (16.01.2003) PCX WO 03/005015 Al

(51) International Patent Classification^: GOIN 27/403,
27/327, 33/66

(21) International Application Number: PCT/KROl/01702

(22) iDteraational Filing Date: 10 October 2001 (10.10.2001)

(25) Filing Language: English

(26) Publication Language: English

(30) Priority Data:
2001/40690

7 July 2001 (07.07,2001) KR

(71) Applicant (for all designated States except US): INFOPIA
CO., LTD. [KR/KR]; A-1603, Dongil Technotown,
Kwanyang-2-Dong, Dongan-Gu, Anyang-Si, Kyunggi-Do
431-716 (KR).

(72) Inventors; and

(75) Inventors/Applicants (for US only): BAE, Byung-woo
[KR/KR]; 101-1911 Samick Apt, 766-4 Hokye-Dong,
Dongan-Gu, Anyang-Si, Kyunggi-Do 431-080 (KR).
KANG, Byung-soo [KR/KR]; 215-201, Jugong Apt.,'
Wonmun-Dong, Kwachon-Si, Kyunggi-Do 427-030
(KR). PARK, Seong-gi [KR/KR]; 109-804, Samsung
4-Cha Apt, Pungdukchon-Ri, Suchi-Eup, Yongin-Si,
Kyunggi-Do 449-846 (KR). LEE, Seong-dong [KR/KR];
365, Hyojung-2-Dong, Hwasan-Myun, Youngcheon-Si,
Kyungsangbuk-Do 770-852 (KR). KWON, Ml-joong
[KR/KR]; 151-52. Gasan-Dong, Kumchon-Gu, Seoul
153-023 (KR).

(74) Agent: L & K PATENT FIRM; 701, Daekun Bldg., 822-5
Yeoksam-Dong, Kangnam-Gu, Seoul 135-080 (KR).

(81) Designated States (national): AE. AG, AL. AM, AT, AU,
AZ. BA, BB, BG, BR, BY, BZ. CA, CH, CN, CO, CR, CU.

[Continued on next page]

(54) Title: GLUCOSE STRIP SENSOR AND GLUCOSE MEASUREMENT METHOD USING THE GLUCOSE STRIP SEN-
SOR

(57) Abstract: Disclosed is a disposable glucose strip sensor config-
ured to rapidly and conveniently measure the concentration of glu-
cose in blood and a glucose measurement method using the glucose
strip sensor. In the glucose strip sensor, at least one checking elec-
trode (33) is additionally provided at an electrode section (30) in-
cluding an operating electrode (31) and a counter electrode (32). The
checking electrode (33) serves to check whether or not it is electri-
cally connected with the counter electrode (32), upon measuring the
concentration of glucose in a blood sample introduced in the sen-
sor. Where two checking electrodes are provided, it may be checked
whether or not an elecUical connection is esUiblished between those
checking electrodes. Based on the result of the checking, it is possi-
ble to determine whether ornot a sufBcienl amount of blood sample
is filled in the sensor. Accordingly, the measurement of glucose con-
centration can be accurately achieved.

wo 03/005015 Al lilliliiliillllliililiiiiiDiiii

CZ, DE, DK. DM. DZ. EC. EE, ES, FI. GB. GD. GE. GH.
GM. HR. HU, ID, lU IN, IS. JP, KE, KG. KP, KZ, LC. LK.
LR, LS. LT. LU, LV, MA. MD, MG, MK. MN, MW, MX.
MZ. NO, NZ. PH. PL, PT, RO. RU, SD. SE, SG. SI. SK,
SL, TJ, ™, TR, TT. TZ, UA, UG, US. UZ. VN. YU. ZA.
ZW.

IT, LU. MC, NL, PT. SB. TR), OAPI patent (BF, BJ, CF.
CG, CI, CM, GA, GN. GQ, GW. ML, MR, NE. SN, TD,
TG).

Published:

— with iniernational search report

(84) Designated States (regional)-, ARIPO patent (GH, GM,

KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), Eurasian For two-letter codes and other abbreviations, refer to the "Guid-

patent (AM, AZ, BY. KG, KZ, MD, RU, TJ, TM), European ance Notes on Codes and Abbreviations " appearing at the begin-

patent (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR. IE, ning of each regular issue of the PCT Gazette.

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PCT/KROl/01702

GLUCOSE STRIP SENSOR AND GLUCOSE MEASUREMENT METHOD
USING THE GLUCOSE STRIP SENSOR

BACKGROUND OF THE INVENTION ^ -

Field' of the Invention

The present invention relates to a disposable glucose
strip sensor configured to rapidly and conveniently measure
the concentration of glucose in blood and a glucose
measurement method using the glucose strip sensor.

Description of the Related Art

The measurement of the concentration of glucose in blood
is of great importance not only to diabetic patients who must
control their sugar intake, but also for the early detection
and diagnosis of diabetes. To this end, methods for simply
and conveniently measuring the concentration of glucose in
blood have been proposed.

Known glucose measurement methods are based on oxidation
of glucose by glucose -oxidase and peroxidase. They also use
orthotolidine or a benzidine-based mixture as an indicator
reagent, that is, a chromogen. In accordance with these
methods, a color transition of the indicator reagent resulting
from the oxidation of glucose is observed to measure the
concentration of glucose in blood.

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For example, such techniques are disclosed in U.S.
Patent No. 3,061,523 and Japanese Patent Publication No. Sho.
50-39558, In these references, a glucose -measuring test piece
is disclosed. In order to prepare this test piece, a solution
5 is prepared which has a composition including: glucose oxidase
and peroxidase as enzymes; a citric acid buffer to maintain a
pH of 6.0/ gelatin, alginic acid, polyvinylpyrrolidone, and
polyvinyl alcohol as stabilizers; and orthotolidine,
benzidine, 3-aminopropylcarbarsone, and 2,7-diaminofluorene as

10 a chromogen. The solution , is impregnated into a cellulose
paper which has a desired thickness and size to be used as a
carrier, and then dried. Thus, the test piece is obtained.
Also, Korean Patent Laid-open Publication No. 85-1297
discloses a method for manufacturing a glucose -measuring test

15 piece, to which the basic principle of an enzymatic
measurement method using glucose oxidase and peroxidase is
applied. Where the concentration of glucose in blood is
measured using the above mentioned glucose -measuring test
pieces, it is difficult to accurately measure a glucose

20 concentration because the measurement is based on a color
transition exhibited on the test piece.

In order to solve the above mentioned problem, various
techniques have been proposed which measure glucose
concentration using an electrochemical method. Such an

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electrochemical method makes it possible to measure the
concentration of glucose in blood with an increased accuracy
while reducing measurement time and achieving convenience in
measurement. By virtue of such advantages, the use of the
electrochemical glucose measurement method has been greatly
increased.

. Now, the operating principle of a glucose -measviring
sensor based on an electrochemical method will be described.
When a blood sample is applied to a reaction layer of the
glucose-measuring sensor, glucose contained in the blood
satrple is oxidized by a glucose-oxidizing enzyme contained in
the reaction layer. At this' time, the glucose-oxidizing
enzyme is reduced. Hie reduced glucose -oxidizing enzyme is
then oxidized by an electron acceptor, whereby the electron
acceptor is reduced. . The reduced electron acceptor donates
electrons at the surface of an electrode to which a desired
voltage is applied. As a result, the electron acceptor is
electrochemically reoxidized. The concentration of glucose in
the blood sample is proportional, to the amount of current
generated during the process in which the electron acceptor is
oxidized. Accordingly, the concentration of glucose can be
measured by measuring the amount of current.

An example of the above mentioned glucose -measuring
sensor is disclosed in Japanese Patent Laid-open Publication

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No. .^61-294351. This sensor is illustrated in Fig. 1. As
shown in Fig, 1, operating and counter electrodes, which are
made of carbon or the like, are formed on a substrate 111 in a
screen printing fashion. An insulator 115 is also formed on
the substrate 111 while allowing the electrodes to be
partially exposed. A porous reaction layer 117, which
contains a reactive material such as a glucose-oxidizing
enzyme and an electron acceptor, is arranged on the insulator
115. In order to firmly hold the porous reaction layer 117, a
holding frame 116 and a cover 118 are arranged on the
insulator 115. In Fig. 1, reference numerals 112, 113, and
114 denote the operating and counter electrodes, and reference
numerals 112', 113', and 114' denote the exposed portions of
the operating and counter electrodes. These electrodes and
electrode portions foirm an electrode system. When a blood
sample is dropped onto the porous reaction layer 117, the
glucose-measuring sensor having the above mentioned structxire
can measure the concentration of glucose in the blood sample.

In this glucose -measuring sensor, however, the amount of
blood absorbed in the reaction layer 117 varies depending on
the amount of the blood sample dropped onto the reaction layer
117. As a result, measurement errors may be caused by a
variation in the amount of blood absorbed in the reaction
layer 117.

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In order to solve this problem, a biosensor has been
proposed. An example of such a biosensor is disclosed in U.S-
Patent No. 5,120,420 and illustrated in Fig. 2. As shown in
Fig, 2, this biosensor includes a non-conductive siobstrate 211
5 made of polyethylene terephthalate. Silver is screen-printed
on the non-conductive substrate 211 to form leads 212 and 213.
Conductive carbon paste containing a resin binder is printed
on the leads 212 and 213, thereby forming an operating
electrode 214 and a counter electrode 215. An insulator 216

10 is then printed to allow the electrodes 214 and 215 to be
partially exposed. A 0.5% aqueous solution of carboxymethyl
cellulose (CMC) is spread onto the electrodes 214 and 215, and
dried to form a CMC layer, . A solution of glucose oxidase
(GOD) as the enzyme in a phosphate buffer solution is spread

15 on the CMC layer, and dried to form a main reaction layer
comprised of a CMC-GOD layer. Next, a resin plate 217 and a
cover 219 are attached to the resulting structure while
defining a space 218. In Fig, 2, the reference numeral 220
denotes a sample introducing port, and the reference numeral

20 221 denotes a discharge port.

In the biosensor having the above mentioned structure,
when a sanple solution comes into contact with the sample
introducing port 220, it is introduced into the space 218 by
virtue of capillary phenomenon, so that it fills the space

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218. Simultaneously, air existing in the space 218 is vented
from the space 218 through the discharge port 221 formed
opposite to the sample introducing port 220 or at the cover
219.

Where the discharge port 221 is arranged at the upper
surface of the biosensor, measurement errors may occur when
the user unintentionally touches the discharge port 221. For
this reason, there is inconvenience in handling the biosensor.
FLirthermore, the user can check whether or not a sufficient
amount of sample solution is introduced in the biosensor, only
with the naked eye. So, the measurement may be carried out
even when an insufficient amount of sample solution is filled
in the biosensor. In this case, however, the detected glucose
level may erroneously be lower than the actual glucose
concentration .

SUMMARY OF THE I3SIVENTI0N

The present invention has been made in view of the above
mentioned problems involved with the conventional glucose-
measuring sensors, and an object of the invention is to
provide a glucose strip sensor including a sample introducing
port arranged at a front surface of the sensor, and discharge
ports respectively arranged at opposite side surfaces of the

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sensor, thereby being capable of achieving convenience in
handling the sensor, while additionally including a checking
electrode adapted, alone or along with a counter electrode, to
determine whether or not a sufficient anoimt of blood sairple
5 is introduced in the sensor, thereby being capable of
achieving cui accurate glucose measurement, and to provide a
glucose measurement method using the glucose strip sensor .

In accordance with one aspect, the present invention
provides a glucose strip sensor comprising a non- conductive

10 substrate, a lead section formed on the substrate, the liead
section including leads and lead terndnals, an ' electrode
section formed on the lead section and provided at an upper
surface thereof with a reaction layer, the electrode section
including an operating electrode, a counter electrode, and a

15 checking electrode, a resin plate adapted to define, over the
electrode section, a space for receiving a blood sample, a
cover formed on the resin plate, a satiple introducing port
adapted to introduce the blood sample into the space, and
discharge ports adapted to vent air from the space, wherein:

20 . the electrode section further includes at least one

checking electrode adapted to check whether or not the blood
saitple is completely introduced in the space; and

the lead section further includes a lead and a lead
terminal for the checking electrode.

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The sanple introducing port may be arranged at a front
siirface of the sensor, and the discharge ports are arranged at
opposite side surfaces of the sensor, respectively.

In accordance with another aspect, the present invention
provides a. glucose measurement method conprising the steps of
checking whether or not an electrical connection is
established between the coianter electrode and the checking
electrode included in the glucose strip sensor or between the
checking electrode and another checking electrode, thereby
determining whether or not a blood sample is introduced in the
space in a sufficient amount; and if it is determined the
blood sample is introduced in the space in a sufficient
amount, then measuring a glucose concentration of the blood
sanple in accordance with a well-known method.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other
advantages of the present invention will be more clearly
Tinderstood from the following detailed description taken in
conjunction with the drawings, in which:

Pig. 1 is an exploded perspective view illustrating a
conventional sample-dropped glucose-measuring test piece;

Fig. 2 is an exploded perspective view illustrating a

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conventional glucose -measuring biosensor utilizing capillary
phenomenon;

Fig. 3 is an exploded perspective view illustrating a
glucose strip sensor according to an embodiment of the present
5 invention;

Fig. 4 is a sectional view of the glucose strip sensor
illustrated in Fig. 3;

Fig. 5 is an assembled perspective view of the glucose
strip sensor illustrated in Fig. 3;
10 Fig. 6 is a perspective view illustrating an electrode

arrangement in the glucose strip sensor according to the
present invention;

Fig. 7 is a perspective view illustrating another
electrode arrangement in the glucose strip sensor according to
15 the present invention; and

Fig. . 8 is a graph depicting the correlation of a signal
generated by the glucose strip sensor according to the present
invention with respect to glucose concentration.

20 DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 3 is an exploded perspective view illustrating a
glucose strip sensor according to an embodiment of the present
invention. Fig. 4 is a sectional view of the glucose strip

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sensor illustrated in Fig. 3, Fig. 5 is an assembled
perspective view of the glucose strip sensor illustrated in
Pig. 3.

As shown . in Figs. 3 to 5, the glucose strip sensor
includes a non-conductive substrate 10, a lead section 20
formed on the substrate 10 by a silver ink or an ink mixture
of silver and silver chloride, and an electrode section 30
formed on the lead section 20. The lead section 20 includes
leads 21 and lead terminals 22, whereas the electrode section
30 includes an operating electrode 31, a counter electrode 32,
and a checking electrode 33. The glucose strip sensor also
includes an insulating layer 40 coated on the lead and
electrode sections 20 and 30 while allowing the lead and
electrode sections 20 and 30 to be partially exposed, a
reaction layer 50 formed on the exposed portion of the
electrode section 30, a resin plate 60 formed on the structure
obtained after the formation of the reaction layer 50, and a
cover 70 formed on the resin plate 60. The resin plate 60
defines a space 63, a sample introducing port 61, and
discharge ports 62. The sample introducing port 61 is
arranged at the front surface of the glucose strip sensor,
whereas the discharge ports 62 are arranged at opposite side
surfaces of the glucose strip sensor, respectively.

The glucose, strip sensor of the present invention is

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characterized in that it includes, in addition to the
operating electrode 31 and counter electrode 32, the checking
electrode 33 for checking whether or not a sanple is
conpletely introduced in the sensor. The glucose strip sensor
of the present invention is also characterized in that the
sanple introducing port 61 is arranged at the front sxirface of
the glucose- strip sensor, whereas the discharge ports 62 are
arranged at opposite side surfaces of the glucose strip
sensor, respectively.

Now, the fabrication of the glucose strip sensor having
the above described structure will be described in detail.

First, the substrate 10 is prepared. For the substrate
10, a polymer substrate may be used which is made of a non-
conductive material such as polyethylene terephthalate,
polyvinyl ' chloride resin, or polycarbonate resin. The
siibstrate 10 is preferably made of polyethylene terephthalate,

The foannation of the lead section 20 on the substrate 10
is then performed. As mentioned above, the lead section 20
includes the leads 21 and lead terminals 22. The lead section
20 may be formed using a well-known screen printing method.
In accordance with the present invention, the lead section 20
is formed by screen-printing a silver ink or an ink mixture of
silver and silver chloride on the substrate 10.

After formation of the lead section 20, the electrode

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section 30 is formed on the lead section 20. In accordance
with the present invention, the electrode section 30 includes
the checking electrode 33 in addition to the operating
electrode 31 and counter electrode 32. Although one checking
electrode 33 is illustrated, the electrode section 30 may
include two or more checking electrodes. Where the checking
electrode 33 is arranged as shown in Fig. 6, it is checked
whether or not the checking electrode 33 is electrically
connected with the counter electrode 32. Based on the result
of the checking, it is possible to determine whether or not
the blood sarnple is sufficiently filled in the sensor.
Accordingly, the glucose concentration in the blood sample can
be accurately measured.

Under the condition in which the checking electrode 33a
determines that a sufficient amount of blood sample is
introduced in the sensor,, the checking electrode 33 can
perform the same function as the counter electrode 32 because
the checking electrode 33 is electrically connected with the
coianter electrode 32. In this case, an increased counter
electrode area is obtained. By virtue of such an increased
counter electrode area, it is possible to obtain a glucose
measuring signal with an increased sensitivity when the amount
of current flowing between the operating electrode and the
coimter electrode is measured. The operating electrode 31 and

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I

counter electrode 32, which form the electrode section 30, may
be formed using a well-known method. The formation of the
checking electrode 33 may also be achieved in the same manner
as the formation of the comter electrode 32. As mentioned
5 above, the electrode section 30 is preferably formed in
accordance with a screen printing method using a conductive
carbon ink.

oh the upper surface of the resulting structure obtained
after formation of the electrode section 30/ an insulating

10 material is screen-printed to form the insulating layer 40 for
insulating the lead section 20 while partially esqposing the
electrode section 30. For the insulating material, a non-
conductive screen printing ink or an insulating ink may be
used- In accordance with the present invention, the

15 insulating screen printing ink is preferably used.

Thereafter, the formation of the reaction layer 50 is carried
out in such a fashion that the reaction layer 50 covers the
exposed portion of the electrode section 30. The reaction
layer 50 is made of a material including hydrogel and glucose

20 oxidase (GOD) as major components thereof. In detail, the
formation of the reaction layer 50 is achieved by preparing a
solution obtained by respectively mixing hydrogel, GOD and a
stabilizer in a liquid buffer at desired rates, dispensing the
solution onto the surface of the electrode section 30, and

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then drying the dispensed solution in an incubator.

On the resulting structure obtained after formation of
the reaction layer 50 including hydrogel and GOD as major
components thereof, a resin plate 60 is arranged to define a
5 space 63. Also, the resin plate 60 defines the. sample
introducing port 61 at the front surface of the sensor and the
discharge ports 62 at respective side surfaces of the sensor.
Since the sample introducing port 61 and discharge ports 62
are formed at the front and side surfaces of the sensor,

10 respectively, ' it is possible to conveniently handle the
sensor, as compared to the conventional sensor including a
discharge port formed at the upper surface of the sensor.

The cover 70 is finally arranged on the resin plate 60
using a well-known method. Thus, the fabrication of the

15 glucose strip sensor according to the present invention is
completed.

Since the glucose strip sensor having the above
mentioned structure includes the checking sensor 33, it is
possible to check whether or not the checking sensor 33 is
20 electrically cormected with the counter electrode 32, thereby
determining whether or not the sensor is filled, with a
sufficient amount of blood sample. Accordingly, there is an
advantage in that the measured glucose concentration has an
increased accuracy. In addition, where the amount of current

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flowing between . the counter electrode 32 and the checking
electrode 33 is -measured under the condition in which those
electrodes are electrically connected using conduction means /
there is an advantage in that a glucose measuring signal with
an increased sensitivity can be obtained. Since the sample
introducing port 61 and discharge ports 62 are formed at the
front and side surfaces of the sensor, respectively, it is
also possible to conveniently handle the sensor.

In the case of Fig. 3, the arrangement of the operating
electrode 31, coimter electrode 32, and checking electrode 33
is made in such a fashion that the counter electrode 32 and
checking electrode 33 are arranged at front and rear sides of
the operating electrode 31, respectively. However, other
arrangements may be implemented.

For example, the counter electrode 32 may be arranged
near the sample introducing port 61, and the checking
electrode 33 may be arranged near one of the discharge ports
62, as shown in Fig. 6. In this case, the checking electrode
33 is electrically connected with the counter electrode 32
under the condition in which the space 63 of the sensor is
completely filled with a blood sample. Accordingly, it is
possible to accurately check whether or not the space of the.
sensor is conpletely filled with a blood sample even when the
space has an increased volume.

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It is also possible to arrange the checking electrode 33
near the sarrple introducing port 61 while arranging the
counter electrode 32 in rear of the operating electrode 31, as
shown in Fig. 7.

Using the checking electrode having the arrangement •
illustrated in Fig. 6 or 7, it is possible to accurately
determine whether or not a sufficient amount of blood sample
is introduced in the sensor. Accordingly, measxirement errors
can be reduced.

The operation of the glucose strip sensor having the
above described structure according to the present invention
will now be described in detail. When a blood sample comes
into contact with the sample introducing port 61 of the
sensor, it is introduced into the space 63 of the sensor by
virtue of capillary phenomenon, so that it fills the space 63 .
Simultaneously, air existing in the space 63 is vented from
the space 63 through the discharge ports 62 respectively
formed at opposite side surfaces of the sensor. Thereafter,
it is checked, prior to a desired measurement of glucose
concentration, whether or not a sufficient amount of blood
sample is introduced in the space 63. That is, it is checked
whether or not an electrical connection is established between
the counter electrode 32 and the checking electrode 33.

The blood sample filled in the space 63 of the sensor is

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inpregnated into the reaction layer .50. The glucose of the
inpregnated blood sample enzymatically reacts with the GOD
contained in the reaction layer 50, so that it is oxidized,
Simultaneously, the GOD is reduced. The reduced GOD is then
oxidized as it reacts with the electron acceptor contained in
the reaction layer 50, whereas the oxidized GOD reacts with
the glucose not yet oxidized. The reduced electron acceptor
migrates to the surface of the operating electrode 31, to
which voltage of about 0.6 V is applied, and donates electrons
at that' siorface. Simultaneously, the electron acceptor is
reoxidized so that it takes part again in the above reaction.
The current generated during the oxidation of the electron
acceptor is proportional to the concentration of glucose in
the blood sample. Accordingly, the glucose concentration in
the blood sample can be quantitatively derived by measuring
the amount of current flowing between the operating electrode
31 and the counter electrode 3.2.

An experiment was made in order to identify correlations
established between the glucose concentration measured by the
glucose strip sensor according to the present invention and
the glucose concentration measured by an automatic glucose
analyzer. The experiment was carried out as follows.

First, a blood sample was prepared by dissolving a
desired amount of glucose in a buffer solution. Thereafter,

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the concentration of glucose in the blood saiiple was measured
using an automatic glucose analyzer , which is the Model YSI
2300 STAT PLUS manufactured by YSI Inc. The signal intensity
corresponding to the measured glucose concentration was then
measured by the glucose strip sensor according to the present
invention. The correlation between the measured glucose
concentration and the measured signal intensity is depicted in
Fig. 8. The measurement was repeated 6 times for each glucose
concentration .

Refeinring to Fig. 8, it can be seen that the correlation
between the measured glucose concentration and the measiired
signal intensity is well established in a clinically important
glucose concentration range, that is, a glucose concentration
range of 50 to 600 mg/dL.

As apparent from the above description, the present
invention provides a glucose strip sensor in which a checking
electrode is additionally provided at an electrode section
including an operating electrode and a counter electrode- The
checking electrode serves to check whether or not it is
electrically connected with the counter electrode, upon
measuring the concentration of glucose in a blood sanple
introduced in the sensor. Based on the result of the
checking, it is possible to deteiiTuine whether or not a
sufficient amount of blood sample is filled in the sensor.

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Accordingly, the measurement of glucose concentration can be
accurately achieved. Moreover, where the amount of ciirrent
flowing between the counter electrode . and the checking
electrode is measured umder the condition in which those
electrodes are electrically connected using conduction means,
there is an advsuitage in that a glucose measuring signal with
an increased sensitivity can be obtained.

In accordance with the present invention, the glucose
strip sensor also includes a sample introducing port arranged
at the front surface of the sensor, and discharge ports
arxanged at respective side surfaces of the sensor.
Accordingly, it is also possible to conveniently handle the
sensor .

Although the preferred embodiments of the invention have
been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
sxabsti tut ions are possible, without departing from the scope
and spirit of the invention as disclosed in the accompanying
claims .

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WHAT IS CLAIMED IS: .

A glucose strip sensor corrprising a non- conductive
substrate, a lead section formed on the substrate, the lead
section including leads and lead terminals, an electrode
section formed on the lead section and provided at an upper
surface thereof with a reaction layer, the electrode section
including an operating electrode, a counter electrode, and a
checking electrode, a resin plate adapted to define, over the
electrode section, a space for receiving a blood sample, a
cover formed on the resin plate, a sample introducing port
adapted to introduce the blood sanple into the space, and
discharge ports adapted to vent air from the space, wherein:

the electrode section further includes at least one
checTcing electrode adapted to check whether or not the blood
sample is completely introduced in the space; and

the lead section further includes a lead and a lead
terminal for the checking electrode.

2. The glucose strip sensor according to claim 1,
wherein the sartple introducing port is arranged at a front
surface of the sensor, and the discharge ports are arranged at
opposite side surfaces of the sensor, respectively.

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3. The glucose strip sensor according to claim 1 or 2,
wherein:

the coumter electrode is arranged near the sarnple
introducing port, and the checking electrode is arranged in
5 rear of the operating electrode; or

the checking electrode is arranged near the sarnple
introducing port, and the counter electrode is arranged in
rear of the operating electrode.

10 4. The glucose strip sensor according to claim 1 or 2,

wherein:

the counter electrode is arranged at the sairple
introducing port, and the checking electrode is arranged at
one of the discharge ports; or
15 the counter electrode is arranged at one of the

discharge ports, and the checking electrode is arranged at the
sarnple introducing port,

5, A glucose measurement method cornprising the steps of:
20 introducing a blood sarrple into the glucose strip sensor

according to claim 1 or 2 ;

checking whether or not an electrical connection is
established between the counter electrode and the checking
electrode included in the glucose strip sensor or between the

21

checking electrode and another checking electrode, thereby
determining whether or not the blood* sairple is introduced in
the space in a sufficient amount; and

if it is determined the blood sample is introduced in
the space in a sufficient amount, then measuring a glucose
concentration of the blood sattple in accordance with a well-
known method.

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PCT/KROl/01702

wo 03/005015

PCT/KROl/01702

3/6

FIG. 3

wo 03/005015

PCT/KROl/01702

wo 03/005015

PCT/KROl/01702

5/6

FIG. 6

wo 03/005015

PCT/KROl/01702

INTERNATIONAL SEARCH REPORT

International application No.

PCT/KR 01/01702

CLASSIFICATION OF SUBJECT MATTER

IPC'^: G01N 27/403. G01N 27/327, G01N 33/66

According to International Patent Classification (IPC) or to both national classification and IPC

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)

IPC^ G01N

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched

AT - Patent documents

Electronic data base consulted during the international search (name of data base and, where practicable, search terms used)

WPI Database, Derwent Publications Ltd.. INTERNET

C. DOCUMENTS CONSIDERED TO BE RELEVANT

Category Citation of document, with indication, where appropriate, of the relevant passages

Relevant to claim No.

wo 00/79258 A1 (ABBOTT LABORATORIES)
28 December 2000 (28.12.00)

the whole document, esp. claims, figures,
the whole document, esp. claims, figures.

WO 99/58709 A1 (ABBOTT LABORATORIES)
18 November 1999 (18.11.99)
the whole document, esp. claims, figures,
the whole document, esp. claims, figures.

WO 99/13100 A1 (ABBOTT LABORATORIES)

18 March 1999(18.03.99)

the whole document, esp. claims, figures.

the whole document, esp. claims, figures.

WO 99/13099 A1 (ABBOTT LABORATORIES)
18 March 1999 (18.03.99)
the whole document, esp. claims, figures,
the whole document, esp. claims, figures.

1-3,5
4

1-3.5
4

1-3,5
4

1-3,5

Further documents are listed in the continuation of Box C.

See patent family annex.

* Special categories of cited documents:

document defining the general state of the art which is not

considered lo be of particular relevance
..E" earlier application or patent but published on or after the international

filing date

„L** document which may throw doubts on priority claim(s) or which is
cited to establish die publication date of another citation or other
special reason (as specified)

„0" document referring to an oral disclosure, use, exhibition or other
means

J^' document published prior to the mtematlonal filing dale but later than
the priority date claimed

„T** later document published after the international filing date or priority
date and not in conflict with the application but cited lo understand
the principle or theory underlying the invention
,,X** document of particular relevance; Uie claimed invention cannot be
considered novel or cannot be considered to involve an inventive step
when the document is taken alone
„Y" document of particular relevance; the claimed invention cannot be
considered to involve an inventive step when the document Is
combined with one or more other such documents, such combi nation
being obvious to a person skilled in the an
„&" document member of the same patent family

Date of the actual completion of the international search

23 January 2002 (23.01.2002)

Date of mailing of the international search report

14 March 2002(14.03.2002)

Name and mailing adrcss of the ISA/AT

Austrian Patent Office
Kohlmarkt 8-10; A-1014 Vienna
Facsimile No. 1/53424/535

Authorized officer

WENIGER

Telephone No. 1/53424/34 1

Fonn PCT/ISA/210 (second sheet) (July 1998)

INTERNATIONAL SEARCH REPORT

interoational application No.

PCT/KR 01/01702

C (Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT

Categoiy*

Citation of document, witli indication, wliere appropriate, of the relevant passages

Relevant to claim No.

X

A
X

A

WO 00/73778 A1 (NOVA BIOMEDICAL CORPORATION)

7 December 2000 (07. 1 2.00)

the whole document, esp. claims, figures.

the whole document, esp. claims, figures.

WO 00/73785 A2 (NOVA BIOMEDICAL CORPORATION)

7 December 2000 (07.12.00)

the whole document, esp. claims, figures.

the whole document, esp. claims, figures.

1-3,5

4
1-3,5

4

Form PCT/ISA/210 (continuation of second sheet) (July 1998)

INTERNATIONAL SEARCH REPORT

Information on patent family members

Intcmaoonal application No.

PCT/KR 01/01702

Patent document cited Publication Patent family Pubfication

in search report date member(s) date

wo

A

073778

none

wo

073785

wo

'WO

QQ1 "anDO

AX

BR

A

9B11609

05-09-2000

EP

Al

1009851

21-06-2000

JP

T2

01516038

25-09-2001

wo

Al

9913X00

18-03-1999

AU

Al

91297/98

29-03-1999

AU

B2

742574

■ 10-01-2002

BR

A

9812017

26-09-2000

EP

Al

1012326

28-06-2000

JP

T2

01516039

25-09-2001

WO

Al

9958709

18-11-1999

AU

Al

38358/99

29-11-1999

BR

A

9910284

09-01-2001

EP

Al

1075538

14-02-2001

GB

AO

9809963

08-07-1998

GB

Al

2337122

10-11-1999

PClV ISA/210 (patent (amfly annex) QmU 1998)

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